Ratio determining device



March 28, 1-944. J; J sHlVELY 2,345,184

RATIO DETERMINING DEVICE Filed 001:. 21, 1939 3 Sheets-Sheet 3 Fig 14240 INVENTOR c/ohn cl- 5hfve/y "ATTORNEYS Patented Mar. 28, 1944 UNITED STATES PATENT OFFICE John J. Shively, New York, N. Y.

- Application October 21, 1939, Serial No. 300,674

Claims. (Cl. 234-55) This invention relates to improvements in ratio determining devices.

An object of the invention is to provide means to determine the relationship between two variable factors.

A further object is to providemeans of the above type in which the rates 01' variation of one or both factors may be variable.

Another object is to provide means 01 the above type by which determination of the relationship may be substantially continuous.

Another object is to provfiie means of the above type adapted to establish the ratio betw cumulative quantities.

Another object is to provide means to create a substantially continuous record of the above determined ratios with respect to a third factor.

Another object is to provide a device of the above nature adapted to the substantially continuous determination o'i' interval power demand.

A still further object is to provide means of a the above nature to maintaih a substantially continuous record of the time-interval demand.

Other objects and advantages of the invention v invention; 5

Figure 2 is a side view of the same partly in section; v

Figure 3 is a top view of the same partly in section:

Figure 4 is a fragmentai detail view of the tripping drum;

Figure 5 is a fragmental detail sectional view of the elevating drum and related parts;

Figure 6 is a vertical partial sectional view of the device showing an alternative form of recording mechanism, the section being taken in the plane 6-4, Figures 7 and 8;

Figure 6-A is a diagram illustrating the geometry of the recording mechanism relating to Figure 6;

Figure 'l is a front elevation of the device shown in Figure 6:

Figure 7--A is a geometrical to Figure '7;

Figure 8 is a top view of the recording linkage diagram relating and related parts shown in Figures 6 and '7;

Figure 9 is a detail view of means to vary and adjust the operation of the recording mechanism;

Figure 101s a detail diagrammatic view of actuatlng means responsive to two variable t actors;

Figure 11 is a diagrammatic illustration of means to initiate control impulses for the device from an electric meter or the like;

Figure 12 is an electrical diagram showing the connections of the actuating means, Figure 10, with suitable meters;

Figure 13 is a similar diagram in which control is exercised Jointly by a meter and a synchronous clock or the like; A

Figure 14 is an'exterior view 0! a unitary structure including, the meter and the ratio-establishing device;

Figure 15 illustrates photoelectric means for deriving impulses for the device from a meter disk;

Figure 16 shows an overload breaker to prevent injury to the mechanism by loads beyond its capacity;

i'or'use when a continuous record is not desired; and

Figure 18 is a iragmental detail view of an alternate form oi tripping drum structure.

Referring to Figure 1, the numeral 10 generally indicates a ratio determining. mechanism having a frame comprising side plates II and 12, .a rear plate 23, a bottom plate 24 and a top plate 25. Two elongated rollers 23 and 21 are journalied one above the other in blocks 23 and 29 secured to the front oi. the side plates ii and 22.

The shaft 30 of the upper roller 23 extends outward beyond the Journal block 23 and has secured thereon a worm gear 3|, Figures 1 and 3. A vertical shaft 32 carries on its upper end a worm 33 meshingwith the gear II and on its lower end a ratchet wheel 34.

The ratchet wheel 34 is equipped with a spring pressed holding pawl 35 and may be driven by any suitable type of magnetic notchlng device 38, herein illustrated as having an electromagnet 31, a swinging armature" cooperative with the magnet, and an elongated hook-shaped pawl 39 pivoted to the armature 30 and normally held forward and in engagement with the ratchet 34 I 2|, revolves the [roller Il clockwise, Figure 2,

a small angle predetermined by the through disposed behind the rollers II and 21 so as to engage the grooves II. The rollers and rods may be made of various materials, but in the embodiment illustrated are made of hard material such as steel or the like. The rods are of accurately uniform diameter so that when pressed into their respective grooves ll they engage the latter in pitch circles of the same diameter throughout.

Rollers 48, Figures 2 and 5, are disposed be-- bind the rods 42 in the ends of angular levers u rockably retained on a transverse rod ll. Tension springs ll. linked between the rear ends of levers I and a transverse strip ll, Figure 2. normally press the rollers 43 against the rods 4! and hold the latter in frictional engagement with the sides ofgrooves II with a pressure willcient to prevent slip between the grooves and rods under the light driving load which must be carried as hereinafter set forth.

The levers II have on their lower sides short extensions ll overlying but clearing the periphery ,of a tripping drum II, shown in detail in Figure 4. A plurality of cam bosses II, one for each lever ll, are disposed in one complete helical turn around the drum It, the longitudinal s acing being such that during a complete turn of the drum each boss ll passes directly under its respective lever 44, engages its extension 48 and rocks the lever clockwise, Figure 2. when any lever, for example a in Figures 2 and 5, is rocked by its cam boss II. the roller In is moved rearwardly as shown in Figure 5, thus removing the pressure from the rod a and releasing the latter from frictional driving engagement with the groove lid. As soon as a boss It moves past the extension 40 of its lever N. the latter is released again allowing the spring 4. to press the rod into engagement with the driving groove.

From the foregoing it will be evident that during one complete revolution of the drum 49 all the rods 4! are successively released or tripped out of driving engagement with the roller 2|, each rod remaining out of engagement while the extension oi the corresponding lever 44 is held upward by its cam boss II.

The drum ll carries on the outer end of its shaft I a ratchet wheel I2 as shown in Figure 4. held from reverse rotation by a second spring pressed pawl II. Figures 2 and '3. It will be understood that the shaft II is iournalled in the side plate II and that the pawl 53 is pivotally attached thereto but for purposes of clarity the side plate II has been partially cut away in Figure 2 to disclose the relation of the working parts.

The ratchet I! has a number of teeth equal to the number of cam bosses It on the drum 4!, and the holding pawl II is so located that in each stop position one lever 44 is held elevated by its respective cam boss.

A second elongated and hook-shaped driving pawl I4 is pivoted at its lower end to a horizontal lever I which in turn is pivotally mounted on the side plate ii. A light diagonal tension spring II, connected between the pawl 54 and lever ll, holds the former in engagement with the ratchet 52. A stronger tension spring 81, hereinafter referred to as the tripper spring, is adjustably fastened to a stationary lug 58 at the bottom and engages the end of lever 55 to urge the latter downward against a suitable stop Bl.

The lever II has a downwardly extending trip latch 80 adapted to be engaged by a spiral cam ii, the latter being secured to a short shaft 82 Journalled in the end plate 2|. When the cam II is revolved counter-clockwise, Figure 2, its gradually increasing diameter forces the lever ll upward throughout the revolution, thus "cocking" the spring I1 and advancing the pawl it one tooth on the ratchet 52. As the cam lobe over-rides the latch 80 into tripping position, the spring I! snaps the lever 55 and pawl 54 downward as shown in Figure 2, thus revolving the ratchet l2 and drum it an amount equal to the angular advdnce of one tooth of the ratchet. This angular distance is equal to that between successive cam bosses lill on the drum it, so that for each tripping of the lever I and incremental rotation of the drum 4!, one lever 44 is released by its cam boss It and the next successive lever 44 is raised by its cam boss. Thus for each rotation of the cam 6| one of the rods 42 is tripped or released from the drum 28 and the rod previously released is reengaged therewith. Since the tripping is accomplished by sudden release of the cocked spring 51, both the release and re-engagement of the rods is practically instantaneous.

In the embodimmt illustrated in Figures 1 to 3. wherein the invention is applied to an alternating current demand meter, the cam 6| is revolved by a small synchronous clock motor 63 through suit. able reduction gearing 64, Figure 1. It will be understood, however, that the cam 6i may be revolved by other suitable means such as that hereinafter described in connection with Figure 10, depending on the type of service to which the device is to be applied.

Vertical rear and front guide rods 65 and II, secured to the top plate 25 and to an upper brace plate 81, form vertical runways for light side carriages it each having grooved rollers 89 and II engaging the rods 88 and single concave rear wheels II engaging the rear rods II. Light but rigid cross members 12 and I3 connect the carriages B8. The rear guide rods 65 are threaded as indicated at I5, and the rear guide wheels II are peripherally hobbed to mesh with the threads of rods 65, the rods 65 and wheels ll thus acting in the relation of fine toothed racks and pinions. The wheels or plnions H are secured on opposite ends of a small but i'igid cross shaft 18 Journalled in the carriages 68. This positive meshing of the rear guide rods or racks 85 with pinions rigidly connected, and therefore forced to revolve together, prevents cocking of the carriage and cross member assembly and ensures parallelism throughout the vertical movements of this assembly irrespective of the point at which the lifting or supporting force is applied thereto.

The lower transverse member 13, hereinafter referred to as the determining bar, overlies the tops of all the rods 42 so as to be movable vertically by any one or more of the latter as hereinafter explained.

Mounted on the top plate type of horizontally moving chart mechanism herein illustrated as having a strip paper chart 11 adapted to be moved from a reel 18 via a platen 19 and a driving sprocket to a second or takeup reel 8|. The sprocket 80 is revolved by a second clock motor 83, Figure 1, through bevel 25 is any suitable gears 04, a vertical shaft and suitable spur gearing 00, Figures 2 and 3. The usual takeup slipping belt 01 maintains the takeup reel 0| firmly wound, and a spring friction washer 00 between the reel and its frame 10a serves to keep the paper II taut across the platen I.

A pen 89 is hinged to the determ g bar It at 90 and is provided with an ink-we OI. The center of weight of the pen and ink-well is normally disposed rearward of the hinge 00 so that gravity normally holds the pen 0! lightly against the paper chart 11.

Figures 13 and 11 illustrate respectively the electrical connections of the device for determining interval electrical demand and a means of initiating control impulses for the device from a meter disk shaft. Referring to the latter figure, the numeral 00 indicates a rotary disk of a meter 0|, the disk 00 being secured to theusual shaft 02 mounted in suitable pivot bearings 03 and 04. A worm 05 on the shaft 02 drives a worm wheel I. on a second shaft 91, the second shaft also carrying a cam .wheel 00. A normally open contactor 99 has a movable member I00 carrying an insulating shoe IOI engaging the cam wheel 00. When the disk 90 revolves theshaft 92 driving the cam wheel 90 through the described gearing, the lobes of wheel 90 successively raise the' circuit closings from a meter shaft or the like is given as purely illustrative, since this may-be;

accomplished in various other ways-such asthat shown in Figure 15, wherein a light beam I05 from a light source I00 normally reflected by the disk I01 to a photocell I00, is successively interrupted by one or more darkened spots I09 on the disk face. The interruptions of the light to the photocell I08 may be translated into circuit impulses by means well known in the art and therefore not further described herein.

Referring to Figure l3, the numerals IIO and I II indicate the conductors of a power line, from which input wires H2 and II 3 are run to the meter 9|, taken for purposes of the present example as representing an A. C. kilowatt hour meter including a circuit closing means such as that'shown in Figure 11. Numerals H4 and H5 indicate the meter output leads or load connec-' tions. The contactor lead I03 is connected to the magnet 31 of the magnetic notcher 36, Figure 1, and the second contactor lead I04 is connected to one side of the low voltage secondary winding IIB of a small transformer III, a third lead H8 in turn connecting the other side-of winding IIG to the magnet 31. The primary winding II9 of transformer III is connected to the conductors H2 and Hit by leads I20 and HI. The purpose of the transformer H6 is to permit the contactor 09 and magnet I I 31 to operate on low voltage, and if in some conductors H2 and Ill, or across the supply lines at any other suitable point.

In the following explanation of the operation of the invention, the latter is applied as an exfrom zero position on a chart, is moved across the chart by the cumulative action of the meter throughout the timeinterval, and at the end of the interval is tripped back to zero to start the next block, the chart meanwhile being fed forward. The result isa series of recordings, each high point recording representing the demand during its particular and set time interval. Such 'a procedure, however, does not give a complete or necessarily accurate record of the actual interval demand of'the system, due to the fact that heavy demands, of considerable duration may occur partly in one block interval and partly in the next, a condition known as peak-, splitting." As anextreme example, the demand may firsthold at 10 kilowatts during the first half of a block interval, may then rise to 1000 kilowatts and continue thereatthrough the remainder of theinterval and half-way through the next interval, then fall again to 10 kilowatts and so continue'to the end of the second interval.v The record produced .by the usual means referred to above would show-two successive intervals with a demand-ch50?) kw. in each. Actually, however, 'duifingxtlie' process there has been a demand of 1000 kw. extending over a time. equal to a full interval, but norecord of a 1000 kw. interval demand occurs on the chart. Such records are used for ascertaining the maximum interval demand, and it is evident that if the above 1000 kw. actually was the maximum the record would not show it but would be inaccurate by any percentage up to 49.5 percent of error.

In the present invention, it will be understood that any practical number of rods 42 and their related elements maybe employed in the structure, depending on the service to which the device is to be put. For purposes of the present explanation, let it be assumed that the apparatus is constructed with thirty-one each of the rods 42. cam bosses 50 and teeth on the ratchet 52, and that it is to be used for recording 5 minute kilowatt demand;

In this case, the camshaft 62, Figures 1 and 2,

is so geared to the synchronous motor 63 as to rotate the cam 6| once in 10 seconds. Thus one oi the rods 42 will be; tripped every '10" seconds,

and all rods will have been tripped once in 5 minutes and 10 seconds. As each 'rod 42 remains disengaged from the roller 26 during one interval between trippings, namely 10 seconds, it is evident that each rod will have been in engagement with'the roller 26 for exactly five minutes.

If any load is on the meter 9|, Figures 11 and 13, the rotation of the disk actuates the dontactor 00 in the manner previously described to successively close the described circuit from transformer III throughthe notching magnet 3'I, and the number of current impulses set up in any given time is proportional to the disk revolutions and consequently proportional to the demand.

Each impulse through the magnet 31 causes the latter to attract the armature 24 and draw the hook pawl 33 .inward, rotating the ratchet 34 by one tooth distance. The rotation of the ratchet 34 is transmitted through the shaft 32, worm 23 and worm wheel ii to the elevating roller. From the foregoing it will be seen that during any period of time the roller 22 is incrementally rotated clockwise, Figure 2, by an amount proportional to the revolutions of the meter shaft during that time. Consequently, all rods 42 in engagement with the diametrically equal pitch lines of the grooves H for any given length of time are moved upward a distance proportional to the meter demand during that time.

It has been set forth that in the present example each rod 42 is held in engagement exactly five minutes. It follows, therefore; that the total upward travel of each nod represents a measure of the demand during the five minutes prior to its release. 80 long as there is any load on the meter after the original the minutes following starting, the rod about to be released, for exampie rod 42b, Figure 1, stands above the following rods which have been in engagement for shorter lengths of time. The transverse determining bar II, Figure l. is supported by the highest rod 42b, and the vertical position of'the pen 89 and consequently the position of the ink mark made thereby on the strip chart I1 is determined by thehelght of the rod about to be tripped. As each rod is tripped the next succeeding one takes up the support of the bar I! and pen as until it in turn is tripped. The pen is thus always controlled by the highest rod, and as the chart moves slowly to the right the pen traces a record curve or mark I24, the upper edge of which at any point on a properly calibrated chart indicates the prior 5 minute demand. As each determining rods travel represents an absolute interval demand, and as these overlapping demand determinations follow each other in rapid succession, it is evident that the curve I24 represents a substantially continuous record of It minute interval demand, without regardto any specific or set block. Using thirty one rods 42 as described above, the greatest possible peak-splitting effect which can occur covers aduration of only ten seconds, thus reducing the'possible inaccuracy of the record by 98.36 percent as compared to the prior recording, means described. Similarly, if 101 rods are used the improvement in accuracy is 99 percent, the greatest possible variation from the absolute, due to peaks, being one-half of one percent. Thus by increasing the number of rods 42 the continuous determination may be carried to any desired limits of precision; however, it will be evident to those skilled In the art that except for special scientific purposes the number of rods need not be large, as with a comparatively small number of rods the invention produces records with precision greater than that of the metering means itself in ordinary service.

In the above mentioned cases wherein a large number of rods is employed the interval between successive trippings may be less than that necessary for the released or idle rod to come properly to rest in zero positions. In such cases, the cam bosses I25, as shown in Figure 18, may be elongated and arranged in overlapping relation on the drum 43. By this means two or more rods 42 may be allowed to idle at the same time, each rod remaining released through two or more trippins peficds.

The lower roller 2! acts as a guide for the determining rods 42 and is revolved thereby. The pressure rollers 43, as shown in Figure 2, are disposed at a level slightly below that of the axis of the drive roller 23, and exert the greater part of their force through rods on the roller 26 to provide ample driving friction for elevating the rods without slip. However, a smaller portion of the pressure is exerted between all active rods and the lower roller 21 so that the latter is revolved in unison with the main drive roller 26 and in turn acts as a secondary driver for the rod sustaining the greatest weight, namely the rod controlling the pen 89 at any given time.

A lower cross member I26, supporting the rods when the latter are in their released or zero position and hereinafter referred to as the zero bar, may be hinged at I21 and I28 as shown in Figures 1 and 2 and provided with an adjustable supporting screw I29. A transverse rod I" rotatably mounted in the side plates 22 and 2 I, has its middle portion cut away as shown in Figure 2 and underlying the rear portions of the levers 44. The rod I30 has in its outwardly projecting end a short cross pin or handle I3I, Figures 1 and 3. When the rod I30 is turned, its cutaway portion acts as a cam to raise the levers 44 and release all engaged rods 42. When it is desired to adjust the device to a newly installed chart strip the rods are released in the above manner while the zero bar I28 is raised or lowered by means of the screw I29 to vertically adjust the zero position of the rods 42 and pen 39.

Obviously the rods 42 may be released in the above manner whenever it is desired to reset the device to zero. For ordinary resetting without adjustment, however, the drum 49 may be manually revolved forward one revolution by means of an exterior knob I32, Figures 1 and 3. This method has the advantage that the rods 42 are released successively, lowering the determining bar is and its attached structures by short steps and consequently without shock.

In the foregoing description'of operation, the device has been shown as determining a substantially continuous ratio between two cumulative factors, one being kilowatt hour consumption and the other being time taken in equal intervals, and for entering the latter factor in the device the trip cam 6| has been described as operated by the synchronous motor 63. For other ratio determinations the cam BI may be actuated by other means, also as previously noted, such means being shown in Figure 10 as follows:

Referring to Figure 10, in which the supporting structures have been cut away to show the relation of the parts most clearly, the cam BI is rotatable by a second magnetic notcher I33 similar to the previously described notcher 36 and comprising an electromagnet I34, an armature I 35 pivotally carrying a spring pressed hook pawl I38 and a ratchet I31 secured to the cam shaft 63. When successive current impulses are applied to the magnet I34 the successive swings of the armature I35 cause the ratchet I31 to be rotated and in turn rotate the cam 62 which cocks and releases the trip-lever 55. With this arrangement, it will be seen that the frequency of tripping the lever 55 and thereby successively tripping the rods 42 is in direct relation to the frequency of impulses sent through the magnet I 34, and that this arrangement permits the entering of two varying factors in the device for determining substantially the ratio of their average values over a period by supplying impulses proportional to the two factors for energizing accuse 5 1 circuit with the notcher magnet 31 as previously described. The numeral I38 indicates a kva.- hour meter also having therein a suitable contactor (not shown) connected to leads I38 and II. The kva.-hour meter I38 maybe connected I in series with the kw.-hour meter by leads 4- and H5, whileleads MI and I4: are provided to connect the meter I38'to the load. The contactor leads are connected in series with the secondcry of transformer II! and the second notching magnet through wires I43, I39 and I48.

It will be understood, of course, that while the main wiring of Figure 2 illustrates a simple single-phase meter arrangement, it is also representative of any desired polyphase system and is intended simply to indicate application of the two meters to the same load.

In operation, impulses derived from the kw.- hour meter 8| actuate the magnet 31 in the manner previously described, causing the rods 42 to be fed upward. At the same time impulses from the kva.-hur meter I88 successively energize the magnet I34 to rotate the ratchet I31 and trip cam i, Figure 10, thereby successively tripping the rods 42. In this case, however, it will be noted that the tripping interval is determined by the number of impulses per revolutionof ratchet I31, this being prearranged by the ratchet ratio and number of contactor closings per revolution of the kva.-hour meter mechanism, in other words, tripping is governed by predetermined increments of kva.-hour accumulation.

Taking again as an example the use of 31 rods 42, and assuming a tripp interval to be determined by 10 kva. hours accumulation, each rod 42 is engaged during the accumulation of 300 kva.-ho urs, independently of the length of time in which this accumulation occurs. The travel of each rod is in turndetermined by the kw.-hour accumulation during the same period of the rods engagement. Thus the height to which each rod rises represents, with respect to a properly calibrated scale or chart 11, a determination of the ratio of kw.-hour accumulation to a given kva.- hour accumulation, this ratio representing the power factor. gagement of any rod 42 during the above accumulation of 300 kva.-hours, the kw.-hour meter accumulates 300 kw.-hours, the point to which the pen 88 is raised on the chart I1 represents 100% power factor. If, however, the kw.-hour accumulation is only 200 per 300 kva.-hours, the rise of the controlling rod 42 will be only twothirds of the above and the pen 88 will indicate and record 66% power factor von the chart. Ex pressed in another manner, the determined result is a ratio between the speeds of the two meters, either or both of which speeds may be and usually are varying factors. The record I24 traced on the chart in the described case would furnish a substantially continuous record of power factor, independently of the magnitude of the demand.

In substantially the same manner the invention may be employed to determine ratios of any simuitaneous functions from which controlling impulses may be applied to it, the record chart in each case of course being properly calibrated for the desired indication. In each case, the action represents a substantially constant process of division in which the elevating factor constitutes For example, if, during the enthe dividend and the tripping factor comprises the divisor. For example, if the second magnetic notcher I33 be controlled by impulses from a cumulative steam flow meter measuring steam input to a turbo-generator and the first magnetic notcher 38 be actuated by impulses from a kw.- hour meter on the generator output, the record produced will be a substantially continuous measure of the over-all efllciency of the turbo-generator. Similarly, if the tripping be controlled from a cumulative oil input meter to an oil-buming generating plant and the rod-elevation be controlled from an output kw.-hour meter, the record produced will continuously show the over all emciency of the plant.

In case for any purpose it is desired toobtain a record representing the inverse or reciprocal of any ratio such as the above, this may be done by interchanging the connections between the two controlling elements and the respective magnetic notchers 36 and I33. As hereinafter set forth, the second synchronous motor 83 which actuates the chart moving mechanism'may also be replaced with a third magnetic notcher, similar to 38 and I33.

The form of the invention shown in Figures 6, '7 and 8 is essentially the same as that already described except that the recording mechanism is modified to employ a swinging pen I44'instead of the straight line motion. The mechanism in this illustration case has its chart mechanism I45 of any suitable type adapted to move the chart I45 vertically, disposed beyond the plate 23 .and viewable from the left in Figure 6, the left The pen arm I4! is hinged to a shaftI48 jour- "naled in a fore-and-aft position on the top of the device. The determining bar I49 forms part of a light but rigid frame I58 having side members I5I and pivoted on a transverse rod I52. Small counterweights' I53 may be provided on the frame I 50 to minimize the effort necessary to lift the bar I48.

' A light yoke member I54 is rotatably and slide.- bly mounted at one end on the pen-arm shaft I48 and at the other end is rotatably mounted on a nut I55, the nut being screwed on a threaded portion I56 of shaft I48 and a sprin washer I51 being provided to retain the member I54 on' the nut as shown In Figure 9. The yoke member I54 has a downwardly curved arm I58 te'rrninating in a tip I58 which engagesa flat plate I50 secured to theframe I58, the uppersurface of plate I68 being disposed in the plane of the bottom of bar I55 and the axis of the pivot rod I52 as shown in Figure 6.

screw I82 is normally so adjusted that the arm tip I59 and. the pen I44 are at with each other about the center of the shaft I48. The weight of the small lever I'8I is sufllcient to overbalance and steady the pen arm I41 when the latteris swung to the left of center, as shown in Figure 7. If desired, the screw "2,. lever I6I and yoke member I54 may be made of steel and one or more of the members magnetized to cause them to cling together as a unit, thus adding part of the weight of the yoke. member to the overbalancing eflect on thepen arm.

The pen I44 may be supplied with ink by any suitable means such as a wick tube I53 swinging in a small ink reservoir I84, Figures 8 and 7, these part being omitted from Figure 8 to preserve maximum clarity in the showing of the pen linkage as previously noted.

In this form of the invention the elevating rods I65 have conical tips I66 giving substantially point contact thereof with the determining bar I49, the rods and bar having surfaces hard enough to normally prevent appreciable wear.

The operation of the determining mechanism is the same throughout as that previously described, except that the bar I49, instead of moving straight upward, swings upward about the pivot rod I52, the plate I60 in turn raising the yoke member I54 and lever I6I to swing the pen I44 across the chart I46.

By reference to the diagrammatic Figure 6-A, it will be seen that by the geometry of similar triangles, upward increments b of movement of the tip I59 are always directly proportional to corresponding upward movements a of the controlling rod tip I66. Referring now to the second diagrammatic Figure 7A, it is evident that as tip I59 and pen I44 are at right angles to each other about shaft I48, the corresponding horizontal movements c of the pen I44 are directly proportional to the movements b of tip I59. It therefore follows that while the pen I44 swings in an arc, its horizontal travel is always directly proportional to the straight vertical travel of the controlling rod or rods I65, and the lateral calibrations of the chart I46 may consequently be uniform.

In case it is desired to change the ratio of travel between the rods I65 and the pen I44, this may be done by adjusting the nut .l55 on the thread I56, thus moving the yoke I54 along the shaft I46 to bring the point of contact of the tip I59 nearer to or farther from the fulcrum rod I52. When all the rods I65 are in initial or reset position as shown in Figures 6, 7 and 8, the face of the plate I66 is preferably parallel to the shaft I46, so that changing the pen ratio as explained above does not alter the'zero position of the pen I44. However, if after the proper pen ratio has been established it is desired to make slight adjustments of the zero position with respect to the chart, this may be done in the manner previously described by raising or lowering the hinged zero-bar I26.

When the device is constructed for one specific service, such as recording interval kw. or kva. demand as previously set forth, the ratio-determining mechanism may advantageously be combined as a unitary structure with the metering elements in a suitable casing I66, Figure 14, the meter containin the impulse controlling means shown in Figure II and presenting the usual cumulative dials I61, while the control connections shown in Figure 13 are contained within the unitary casing.

As the magnetic notchers 36 and I33 or the motor 63 may be made of ample power, the device is rugged in structure and positive in action. The worm and gear drive of the elevating roller 26 is preferably irreversible, relieving the pawl 35 of ratchet 34 of any back-lash or necessary support of the weight of rods 42. It will be evident to those skilled in the art, however, that in certain cases of large and powerful metering means or the like, the elevating or tripping mechanisms or both may be driven directly from the metering devices by any suitable gearing.

For some services it may be desired simply to indicate the maximum value reached by the determined ratio over a period of time rather than keeping a continuous record of the ratio. For such purposes the pen arm I41, Figure '1, may be replaced by an indicating hand I68 as shown in Figure 17, the hand I63 being cooperative with a fixed dial I69 which replaces the moving chart A drum I10 on the shaft I48 is normally restrained from clockwise movement by a friction pawl I1I pressed by a light spring I12, the drum however being free to move counterclockwise. As the determined ratio increases the hand I69 is swung to the right along the dial I69, but if a decrease in ratio occurs the pawl I1! and drum I10 prevent return of the hand to the left. At the end of any period of time, therefore, the position of the hand indicates on the dial the maximum value of the determined ratio during the period. When the instrument is reset the pawl may be released by depressing a button I12 provided thereon, allowing the shaft I48 and hand I68 to return clockwise to zero position. If simple continuous indication of the desired ratio is required, the pawl III and drum I10 may be omitted.

To prevent possible injury to the mechanism by prolonged overloads beyond the capacity of the apparatus, a normally closed breaker I 13 may be placed in series between the notching magnet 31 and the contactor lead I03 by means of a wire I14 as shown diagrammatically in Figure 16. An arm I15, secured to the pen shaft I44, is adapted to open the breaker I13 when the pen arm I41 swings to the right to the limit of its capacity, thus disabling the notching circuit and preventingfurther rotation of the elevating drum 26 until the overload has subsided. Obviously, such a breaker may also be arranged for operation by the cross member 12 in the form of the device shown in Figures 1, 2 and 3.

The longitudinal travel of the strip chart 11 is illustrated in Figure 1 as controlled by the second synchronous motor 83, the chart travel thus being constant with respect to a third factor representing time. However, it has been shown in Figure 10 that the first synchronous motor 63 driving the trip cam 6i may be replaced by the second magnetic notcher I33, and it is obvious that in the same manner a third notcher of the same type may be substituted in the same manner for the second motor 83, thus permitting the chart travel to be controlled by a third factor other than time, which third factor may itself be a variable. An example of the use of such an arrangement would be the continuous determination of the power factor of a motor driving a water pump under increasing load as the pump fills an elevated water tank of uniform diameter from a bottom inlet. In this case, the longitudinal calibrations of the chart would be in terms of water head, the chart travel being suitably controlled by a cumulative flow meter on the water pipe or by a moving depth gage in the tank. In any application of the device the slope of the curve drawn on the chart represents at any point the first differential or rate of variation of the determined ratio with respect to the factor controlling the chart travel.

While the device has been illustrated and described in preferred form, it is not limited to the exact embodiments and uses set forth, as it is obvious that the determining mechanism may be used for many other purposes and that various changes and modifications may be made without departing from the scope of the appended claims.

What is claimed is:

1. In a ratio-determining device, in combination, a driving roller, a plurality of movable parallel rodstangentially disposed with respect to aims to normally hold said rods in frictional ii relation with said roller, means to rotate said roller whereby said rods may be moved, a common movable member engageable in pushing relationship by each of said movin rods and adapted to be positioned thereby, means to successively release said rods from said roller, and means associated with said common movable member to present a continuous indication of the position thereof.

2. In a ratio-determining device, in combination, a driving roller, a plurality of parallel rods disposed tangentially with respect to said roller, said rods having a common zero position, means to impart rotation to said roller, means to successively place saidrods in driving engagement with said roller during overlapping time intervals whereby said rods may be moved distances proportional to the rotation of said roller during said intervals, means to determine the duration of said intervals, and common means successive- 1y operable by each of said engaged rods to indicate the terminal positions of said rods relative to said zero position.

3. The combination claimed in claim 2'wherein said interval determining means includes a constant speed motor and tripping mechanism assdciated with said rods and operable by said motor whether said overlapping intervals may be of equal duration.

4. In a device of the character described, in combination, a frame, a rotatable elevating roller journalled therein, a rotatable drum iournalled in said frame and having its axis parallel to the axis 'of said roller, a plurality of vertically movable rodsadjacent said roller, a plurality of levers pivotally mounted in said frame and adjacent said drum, pressure rollers on said levers and adapted to individually engage said rods. resilient means attached to, said levers for normally press ing said pressure rollers against said rods to hold said rods in driving engagement with said elevat- 8 ing roller, a plurality of cam members on said drum and adapted to individually move said levers to release said rods from said elevating roller, said cam members being disposed helically about said drum whereby said rods may be successively 10 released during rotation of said drum, a movable bar overlying allsaid rods and adapted to be successively supported and positioned by each of said rods, and means associated with said bar to trace a record corresponding to the successive 16 relative positions of said bar.

5. In an interval demand recording device, in combination, a frame, a rotatable elevating roller Journalled therein, said roller having a plurality of circumferential grooves, a plurality of paral- 20 lel rods of equal length adjacent said roller and adapted to be elevated thereby, a common stop member underlying said rods, means to rotate said roller, means to successively engage said rods with said grooves in driving relation during successive overlapping time intervals and to suecessively release said rods at the termination of said intervals whereby said rods may be elevated during said periods and thereafter may return by gravity to said stop member, a common bar 0 movably attached to said frame and overlying said rods and adapted to be successively engaged by each of said rods whereby said bar may be continuously supported and positioned by the highest of said rods, a record chart on said frame, means to move said chart, and means controllable by movements of said bar to trace a record on said chart, said record having amplitude proportional to the amplitude of movement oisaid bar.

& JOHN J. BHIVELY. 

